It is known to have in power assisted steering modules and more particularly in electric power assisted modules, a gear reducer comprising a worm which is driven by the assistance motor and which meshes on a worm wheel coupled to the output shaft of the power assisted steering module.
In order to compensate for the gear slack, and thus limit parasitic noise, in particular when the torque transmitted by the reducer is low, it is also known to interpose, between the casing of the power assisted steering module and one of the bearings supporting the worm, a spring designed for pressing said worm radially against the toothing of the worm wheel.
However, it may occur that, as a result of in particular vibrations to which the power assisted steering module is subjected, the spring is displaced along the axis of the worm, to the extent that a noticeable decrease of its useful range of slack compensation is observed, and hence a risk that shocks between teeth and parasitic noise appear or intensify.